I have the same issue. My computer I had been testing on went down late last month. I finally got it going yesterday to be informed I had 2 days left on the beta of Sticky Password. Are you going to release the new version or a new beta key soon? Otherwise I will have to step away from the beta and go back to version 5. Thanks.

If you have sent in email feedback to the team then you can send them an email to request a license that won't expire. I did this when I thought I would not be able to do any more testing and just got a license. Use the email betatest@stickypassword.com to send the request. My computer is back up and the license had expired but the license they sent restored it fully. I hope you get your license too.

I used Gmail to send email without issue. It sounds like they might be listed on a blocklist or more likely your email server is on a blocklist; either way it would require some additional work to find the solution. I only found minimal information on the error when looking it up. Try sending a PM to petr.pinkas here and list you email. I expect he can help solve the issue. Good luck.